Zack Rusin has been working on a lot of Linux graphics code lately from an OpenCL state tracker to other Gallium3D state trackers like X-Video / EXA. On top of this, he has just formally announced his work on bringing Geometry Shaders to Mesa. Geometry Shaders were introduced on the Microsoft side with DirectX 10.0 through Shader Model 4.0 and in the OpenGL world can be found with the most recent 3.2 release (or earlier using the GL_EXT_geometry_shader4 extension). Zack's Geometry Shaders support comes in a patch that's over 30,000 lines of code and touches many different parts of the Mesa 3D stack...